Feeding mechanism for rock drills



NOV. 3, 1936. I L RICHARDSON 2,,U59A-9l FEEDING MECHANISM FOR ROCK DRILLS 7 Filed May 15, 1935 2 Sheets-Sheet l TwE LED L. RICHARDSON INVENTQR BY ATTORNEY ZMEQAM Nov. 3, 1936. L. L. RICHARDSON FEEDING MECHANISM FOR ROCK DRILLS 2 Sheets-sheaf. 2

Filed May 15, 1955 ATTORNEY Patented Nov. 3, 1936 UNITED STATES PATENT OFFICE FEEDING MECHANISM FOR ROCK DRILLS Application May 15, 1935, Serial No. 21,553

11 Claims.

This invention relates broadly to rock drills of the drifter type, but more particularly to a feeding mechanism therefor.

One object of this invention is to provide a rock drill with a new, simple and efficient feeding mechanism capable of feeding the rock drill toward or away from the work.

Another object of this invention is to utilize the force of the jars imparted to the rock drill due to the reversal of the piston strokes therein, for feeding the drill in either direction.

Another object of this invention is to produce a feeding mechanism with a simple and eflicient device readily operable for varying the feeding speed imparted to the drilling motor, or for looking the latter against movement relative to the support on which it is slidably mounted.

Other objects and advantages more or less ancillary to the foregoing and the manner in which the various objects are attained, reside in the specific construction and aggroupment of the elements peculiar to this structure, as will become apparent from a more complete examination of this specification, in the claims of which there are assembled certain specific combinations of parts and specific constructions indicative of the scope and spirit of the invention.

In the drawings which illustrate a preferred form of the invention,

Fig. 1 is a side elevational View of a rock drill having the invention incorporated thereto, the support being shown in section. to illustrate details of construction.

Fig. 2 is an enlarged. sectional view taken through a plane indicated by line 2-2 in Fig. 1.

Fig. 3 is an enlarged view partly in section taken through a plane indicated by line 33 in Fig. 2.

Figs. 4 to '7 inclusive are cross sectional views taken through a plane indicated by line 44 in Fig. 3, illustrating the parts shown therein in diiierent positions.

Figs. 8 to 11 inclusive are views corresponding to Figs. 4 to '7 but taken through a plane indicated by line 8--8 in Fig. 3.

Figs, 12 to 15 inclusive are also views corresponding to Figs. 4 to 'l but taken in a plane indicated by line |2|2 in Fig. 3.

Figs. 16 to 19 inclusive are views partly in section taken through a plane indicated by line |li|6 in Fig. 3, the position of the different parts shown in these figures corresponding to the position of the parts shown in the group of sectional views located on the side thereof.

Fig. 20 is an enlarged side elevational view of one of the pawls shown in the other views.

Referring to the drawings: in which like symbols designate corresponding parts throughout the several views, 2| represents a fluid actuated rock drill or drilling motor of the drifter type. The cylinder 22 of the drilling motor 2| is formed with the usual guides 23 extending the full length thereof for slidable engagement within the usual guideways 24 of a stationary support or shell 25. To the end of the cylinder 22 is also affixed in the usual manner a head 26 havinga throttle valve rotatable therein by a handle 27. Rigidly secured to the underside of the cylinder 22 by a plurality of bolts 28, there is a rectangular housing 29 capable of slidable movement with the drilling motor within the shell 25. This housing is provided with a longitudinally disposed bore 38 having a shaft 3| rotatably mounted therein. One end of this shaft is properly machined to receive a washer 32 secured therein by a nut 33, the washer being capable of engagement with the adjacent end wall of the housing 29 for limiting the slidable movement of the shaft in one direction. The other end of the shaft is conveniently machined to receive a handle 34 rigidly secured therein by a nut 35. The handle 34 extends rearwardly from the end of the shaft 3| to provide adequate hand clearance with the back head 26.

Longitudinally disposed within the housing 29, there are three groups or sets of pawls 36, 31, and 38. Each of said sets comprises a duality of diammetrically opposed pawls. Each of said pawls is a replica of the pawl shown in Fig. 20,

which comprises a relatively wide wing 39, a

the marginal edge of the housing 29, while the narrow wing 4| is capable of movement into the bore 30 through a similar recess 44, leading from the bore 30 into the housing 29. Leading from each of the recesses 44 into the interior of the housing, there is a restricted fiat bottom bore having a plunger 45 slidable therein and constantly urged in engagement with the narrow wing 4| of the pawls, by a compression spring 46.

The periphery of the shaft 3| isaccurately ill machined to provide six earns 41, 48, 49, 55, 5 l, and 52 capable of communication with the semi-circular recesses Ml. These cams are disposed in pairs, each of said pairs being located in longitudinal spaced relation with each other, and in different peripheral location. The cams of each pair are disposed in diametrical opposition and have a land between them constituting a portion of the normal periphery of the shaft. The shaft 3! is also provided with an annular recess or groove 53 having the bottom thereof tapered as at 54, and engageable with one end of a pin 55 which is slidably mounted within an opening formed through the bottom of the housing 29. The other end of the pin 55 is resting on the bottom of the shell 25 for the purpose which will be explained later. Adjacent the handle 35, the shaft 3| is provided with an annular groove 55 having a spring pressed plunger 5'! engageable therein for locking the shaft against accidental longitudinal movement. Carried by the housing 29 there is another spring pressed plunger 53 engageable with radially disposed grooves formed on the inner face of the handle 34 for locking the latter, and consequently the shaft 3!, against accidental rotation.

Each side of the shell 25 below the guideways 24 is formed with a rectangular groove 59 extending the full length of the shell and adapted to receive a rack 60 rigidly secured therein by a plurality of bolts 5|. The two racks G are positioned in opposition to each other and in horizontal alignment with the recesses 43 formed in the housing 29, and are of a width substantially equal to the width of the large wing 39 of the pawls located in the housing 29.

In the operation of the mechanism, let us assume that motive fluid is admitted in the drilling motor 2| for causing the reciprocation of the hammer piston in the cylinder 22, and let us further assume that the handle 34 is positioned as shown in full line in Fig. 2, that is in a vertical position. In this instance the jars imparted to the drilling motor due to the reversal of the hammer piston therein, will cause the forward and backward movement of the drilling motor. With the handle positioned as above mentioned, the cams 4'! to 52 of the shaft 3| are positioned as illustrated in Figs. 4, 8, and 12 thus maintainthe pawls 35, 31, and 38 in the positions shown in Fig. 16 against the effort of the spring pressed plunger 45, and consequently out of engagement with the racks 50. When the handle is thus positioned, it will be understood that since the pawls are maintained out of engagement with the racks 60, the drilling motor is free to move back and forth within the guideways 2 1 of the shell 25, thus permitting the operator to manually push or pull the drilling motor toward or away from the work. Assuming now that the drilling motor has been pushed to the work and the drilling operation is ready to start, the operator may rotate the handle in position A shown in Fig. 2. In this instance the cams. of the shaft 3| are positioned as shown in Figs. 5, 9, 13 thus permitting the wing M of the pawls 35, due to the action of the spring pressed plungers 45 acting thereon, to move in engagement with the cams 41 and 48, and thereby causing the consequential outward movement of the wing 39 of the pawls 36 in engagement with the teeth of the racks 60 as shown in Fig. 1'7. When the pawls are thus positioned, the drilling motor due to the jars imparted thereto, is free to move toward the work with the pawls 3G riding the teeth of the racks, while the movement of the drilling motor away from the work is checked due to the engagement of the pawls 36 with the teeth of the racks 60. With only the pawls 3G engaging the racks 60, it will be noticed that the movement or recoil of the drilling motor is not entirely prevented, but is at least limited to a travel equal to the normal pitch of the teeth of the racks 60. In other words, before the drilling motor is actually fed to the work, it is necessary that the forward movement thereof be sufficient to permit the engagement of the pawls was from one tooth to the other, resulting thereby in a relatively slow feeding speed of the drilling motor. When it is desired to increase the rate of speed of the drilling motor, the handle 35 may be moved in the position B shown in Fig. 2, thus positioning the cams of the shaft 35 as shown in Figs. 6, 10, and 14. In this instance the pawls 36 and 38 are capable of engagement with the racks 6G. The distance between these two pawls is calculated to afford the engagement of one pawl 38 with the teeth of the racks, while the pawls 35 are positioned half-way out of engagement with the teeth of the rack. In this position of the handle 34, the pawls 36 or 38 are moved in engagement with the teeth of the racks 60 after a travel of the drilling motor equal to only one-half of the normal pitch of the teeth, thus materially increasing the rate of feeding speed imparted to the drilling motor.

When it is desired to feed the drilling motor away from the work, the handle 34 may be rotated in the position C shown in Fig. 2, thus positioning the cams of the shaft 3i as shown in Figs. 7, ll, and 15. Due to the rotation of the shaft 3!, the cams 4T, 48, and 52 acting on the narrow wing M of the pawls 35 and 38 will cause the disengagement of the enlarged wing thereof with the teeth of the racks 68, thus positioning the pawls 36 and 38 as shown in Fig. 19, while the pawls 3! are now capable of engagement with the other side of the teeth of the racks 60. In this instance, the drilling motor is capable of free movement in a direction away from the work, while its movement toward the work is limited due to the engagement of the pawls 31 with the teeth of the racks 50.

The drilling motor may be locked against movement relative to the support or shell 25 irrespective of the position of the pawls with respect to the racks 60 by applying a tensional force to the handle 34, thus causing the longitudinal movement of the shaft 3|. During this movement of the shaft, the tapered bottom wall 54 of the annular groove 53 will cause the forcible engagement of the pin 55 with the bottom of the shell, thus creating sufiicient frictional resistance to prevent the movement of the drilling motor relative to the shell 25.

From the foregoing, it will be understood that by securing a rack on each side of the shell 25 in diametrical opposition to each other, and causing the concurrent engagement of each set of pawls with the teeth of both racks, the thrust resulting from the engagement of said pawls with the teeth of their corresponding rack is evenly distributed on both sides of the shell, thus maintaining the motor in longitudinal alignment with the shell, and preventing any lateral forces to be distributed to the motor which would tend to increase the frictional resistance between the motor and shell. It will also be seen that the present construction provides a feeding mechadle 34.

nism for rock drill of simple construction and operation, whereby the jars imparted to the drilling motor are utilized for imparting feeding motion to the motor, the rate of the feeding speed being variable by the simple rotation of the han- Furthermore the direction of the feeding motion may also be controlled by rotating the handle from one position to another, and the drilling motor may be locked against movement relative to the shell by imparting a tensional force to the handle 34.

Althoughthe foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or confining and it is to be further understood that various rearrangements of parts and modification of structural detail may be resorted to Without departing from the scope or-spirit of the invention as herein claimed.

I claim:

1. In a feeding device, the combination with a support having a motor slidably mount-ed thereon, of a hammer piston reciprocable in said motor imparting jars thereto tending to move the motor longitudinally of the support, of a recoil resisting mechanism operatively associated with the motor and the support and comprising a duality of racks secured to said support with the teeth of one of said racks disposed in diametrical opposition to the teeth of the other, pawls between said racks carried by said motor capable of concurrent engagement with the teeth of said racks, and unitary means operable for selectively controlling the engagement of said pawls with the teeth of said racks to enable said motor to move in one direction relative to the support due to the jars imparted tothe former.

2. In a feeding device, the combination with a support having a motor slidably mounted thereon, of a hammer piston reciprocable in said motor imparting jars thereto tending to move the motor longitudinally of the support, of a recoil resisting mechanism operatively associated with the motor and the support and comprising a duality of members secured to said support in opposition to each other, movable elements between said members carried by said motor and capable of concurrent operative engagement with said members, and unitary means operable for selectively controlling the operative engagement of said elements with said members to enable said motor to move in one direction relative to the support due to the jars imparted to the motor.

3. In a feeding device, the combination with a support having a motor slidably mounted thereon, of a hammer piston reciprocable in said motor imparting jars thereto tending to move the motor longitudinally of the support, of a mechanism operatively associated withthe motor and the support and comprising a duality of racks secured to said support with the teeth of one rack in diametrical opposition to the teeth of the other, movable pawls between said racks carried by said motor and capable of concurrent operative engagement with the teeth of said racks to enable the jars imparted to said motor to cause the feeding movement of the latter in one direction, and unitary means operable for causing the concurrent disengagement of said members with the teeth of said racks to enable a free slidable movement of said motor in either direction.

4. In a feeding device, the combination with a support having a motor slidably mounted thereon, of a hammer piston reciprocable in said motor imparting jars thereto tending to move the motor longitudinally of the support, of a mechanism operatively associated with the motor and the support and comprising a duality of racks disposed in opposition to each other with the teeth thereof located therebetween, a housing secured to said motor slidable between said racks, a plurality of pawls for each of said racks carried by said housing and capable of concurrent engagement with the teeth of said racks to enable the jars imparted to the motor to cause the forward or rearward feeding motion of the motor relative to the support, and means operable for selectively controlling the engagement of said pawls with the teeth of said racks, thus controlling the direction of the feeding motion of said motor.

5. In a feeding device, the combination with a support having a motor slidably mounted thereon, of a hammer piston reciprocable in said motor imparting jars thereto tending to move the motor longitudinally of the support, of a mechanism operatively associated with the motor and the support and comprising a duality of racks disposed longitudinally of the support in opposition to each other and a pawl for each of said racks carried by said motor and longitudinally movable therewith between said racks, said pawls being capable of concurrent operative engagement with the teeth of their respective racks to enable the jars imparted to said motor to cause a step by step longitudinal movement of said motor in one direction, and unitary means for selectively controlling the operative engagement of said pawls.

6. In a feeding device,.the combination with a support having a motor slidably mounted thereon, of a hammer piston reciprocable in said motor imparting jars thereto tending to move the motor longitudinally of the support, of a recoil resisting mechanism operatively associated with the motor and the support and comprising a rack and a movable pawl engageable with the teeth thereof to enable the jars imparted to the motor to cause the feeding movement of said motor in one direction, a manually operable element movable in one direction for controlling the engagement of said pawl with the teeth of said rack, and a movement arresting device operatively associated with the motor and the support and operable for locking the former against movement relative to the latter, said device being operable upon movement of said manually operated element in another position.

'7. In a feeding device, the combination with a support having a motor slidably mounted thereon, of a hammer piston reciprocable in said motor imparting jars thereto tending to move the motor longitudinally of the support, of a recoil resisting mechanism operatively associated with the motor and the support and comprising a rack and a pawl engageable with the teeth of the rack to enable the jars imparted to the motor to cause the feeding movement of said motor in one direction, of a movement arresting device operatively associated with the motor and the support and operable for locking the former against movement relative to the latter, and unitary means operable for selectively controlling the engagement of said pawl with the teeth of the rack and the operation of said movement arresting device.

8. In a feeding device, the combination with a support having a motor slidable thereon, of a hammer piston reciprocable in said motor imparting jars thereto tending to move the motor longitudinally of the support, of a recoil resisting mechanism operatively associated with the motor and the support and comprising an elongated toothed member carried by the support and a plurality of elements carried by said motor, said elements being capable of alternative operative engagement with the teeth of said member to enable the jars imparted to said motor to cause the feeding motion of the latter in one direction at a predetermined rate of speed, and unitary means movable in one position for shifting and maintaining some of said elements out of engagement with the teeth of said member for reducing the rate of speed of said feeding motion, and in another position for shifting and maintaining all of said elements out of engagement with the teeth of said member for preventing the feeding motion of said motor resulting from said jars.

9. In a feeding device, the combination with a support having a motor slidably mounted thereon, of a hammer piston reciprocable in said motor imparting jars thereto tending to move the motor longitudinally of the support, of a mechanism operatively associated with the motor and the support and comprising a duality of toothed members carried by the support and a plurality of elements for each of said members carried by said motor, said elements being capable of alternative operative engagement with the teeth of their respective member to enable the jars imparted to said motor to cause the feeding motion of said motor in one direction at a predetermined rate of speed, and means movable in one position for shifting and maintaining some of said elements out of engagement with the teeth of their respec-- tive members for reducing the rate of speed of said feeding motion and in another position for preventing the alternative engagement of all of said elements for causing the feeding motion of said motor at the predetermined rate of speed aforesaid.

10. In a feeding device, the combination with a support having a motor slidable relatively thereto, of a hammer piston in said motor imparting jars thereto tending to move the motor longitudinally of the support, of a mechanism operatively associated with the motor and the support for transforming the jars imparted to the motor in a feeding motion of the latter in one direction, said mechanism including a stationary toothed member and movable elements capable of alternative operative engagement with the teeth of said member, the rate of speed of said feeding motion depending upon the number of said elements capable of alternative operative engagement with said teeth, and means operable for controlling the member of said elements capable of operative engagement with said teeth, regulating thereby the rate of speed of said feeding motion.

11. In a feeding device, the combination with a support having a motor slidable thereon, of a hammer reciprocable in said motor imparting jars thereto tending to move the motor longitudinally of the support in both directions, of a mechanism operatively associated with the support and the motor and comprising a duality of racks disposed longitudinally of the support, a pawl for each of said racks carried by said motor, said pawls being capable of concurrent movement arresting engagement with the teeth of their respective racks to prevent the longitudinal movement of the motor in one direction, said racks and pawls arranged and disposed in a manner whereby the thrust resulting from the movement arresting engagement of the latter with the former is distributed to said support without affecting the frictional resistance between said support and motor, and unitary means for selectively controlling the movement arresting engagement of said pawls with the teeth of their respective rack.

LED L. RICHARDSON. 

